Flatness-based Feedforward and Feedback Control for Fuel Rail System of Gasoline Direct Injection Engine

Abstract

For gasoline direct injection (GDI) engines, obtaining desired rail pressure has become a key prerequisite of fuel injection quantity precise control. Since improved control performance and robustness will translate into better combustion stability, fuel economy and emissions. This paper develops a feedforward-feedback controller based on a nonlinear model of fuel rail system, where nominal feedforward control is derived by differential flatness and fuel rail pressure is selected as flat output. In feedback part, to simplify the design, the system is linearized on equilibrium point using Taylor series expansion, and Lyapunov method is used to ensure stability of closed-loop error system. Finally, the proposed controller is verified by fuel rail system simulation model established in AMESim software package, the simulation results in different pressure references demonstrate the effectiveness of the control system.